1. Field of the Application
This application relates generally to sealed electrical enclosures for use in hazardous locations for a variety of electrical components, such as circuit breakers, motor switches, GFI devices, and photocells.
2. Description of the Related Art
Traditionally, in North America, to use circuit breakers in a hazardous (classified) area, standard circuit breakers are placed in a cast metal housing such as aluminum, wherein the cast metal housing is bolted shut. In such an arrangement, the circuit breaker switches may be manipulated through a cast metal door that is bolted to the cast metal housing. In North America, this construction is suitable for Class I Division 1 and Class I Division 2 applications. A drawback of this arrangement is that the cast iron enclosures are heavy and cumbersome. Furthermore, it can be time consuming and laborious to remove the often extensive number of bolts from the cast metal housing to access the circuit breakers within. Thus, replacing circuit breakers using enclosures with this construction can be time consuming and costly.
Alternatively, in Europe, in accordance with IEC methodology, traditionally each circuit breaker or other electrical device is separately and permanently sealed (often potted in epoxy) to provide a flame proof device. Each flame proof sealed circuit breaker or electrical device is then typically placed in a non-metallic or sheet metal enclosure. Each sealed circuit breaker typically has a handle or switch that extends through a door of the non-metallic or sheet metal enclosure to allow for manipulation of the handle or switch. In the event that a circuit breaker needs to be replaced, the flame proof circuit breaker is removed, and a replacement flame proof circuit breaker installed. A drawback to this methodology is that it is more costly to replace each separately sealed flame proof circuit breakers than it is to replace non-flame proof circuit breakers.
There has been an increased demand for sealed breakers in North America. Thus, there is a need to provide an electrical enclosure for use in hazardous (classified) locations that can provide for the removal and replacement of circuit breakers or other electrical components from a reusable electrical enclosure. For purposes of this application the term “hazardous locations” and “hazardous (classified) locations shall mean areas classified by the National Electric Code (NEC), such as NEC Class I, Division 1 areas.